The present invention relates generally to improvements in foldable packaging cases used for transporting a plurality of products as a single unit, and more particularly to certain improvements in the structure of such cases which enhance the ability of the cases to be readily folded, to be unfolded by automated machinery, and to maintain their desired structural configuration and integrity while transporting said plurality of items as a single unit. An important aspect of the invention is the provision of improved hinge assembly means for carrying out the folding or collapsing functions while at the same time providing a snap-together operative interengagement between the individual portions of the device in order to facilitate replacement of damaged portions of the device.
Collapsible crates in general are known, earlier developments in this regard being represented for example by Hunter U.S. Pat. No. 1,180,294, Hartson U.S. Pat. No. 1,972,483, Smith et al U.S. Pat. No. 2,525,838, Frerking U.S. Pat. No. 2,803,084 and Oakey et al U.S. Pat. No. 3,130,850. Devices of the general types illustrated in these patents include assembly means and hinging mechanisms that are comprised of separate parts that are put together in a variety of ways and by a variety of structures, which leads to expensive production costs and which provides surface irregularities and multiple materials interfaces between these assembled parts, thereby presenting serious cleaning problems and requiring maintainance as the assembled parts loosen with respect to each other during use.
Progress in the collapsible container art in general over these earlier developments and structures is illustrated by Sanders et al U.S. Pat. No. 3,796,342 which describes a container for egg cartons that will collapse vertically and that can be made from molded plastic material parts that are permanently assembled together to the degree that they can be disassembled only with considerable effort, this patent also showing relatively fragile plastic webs as hinges. Another example of a more contemporary collapsible crate structure is that shown in Box U.S. Pat. No. 4,044,910 intended for transporting and storing fruits and vegetables, which container has inwardly folding wall members that are of a unitary construction with the hinge portion of the crate, such unitary hinges taking the form of thin plastic webs that connect the crate base to the side walls, each of which folds on top of the crate base and in some instances on top of one another, such structures taking up a floor space the same size as that taken up by the uncollapsed crate.
By the present invention, a foldable packaging case is provided which avoids the complicated construction aspects, the cleaning difficulties and the maintainance requirements of the earlier approaches to collapsible containers, while at the same time providing a device made of molded plastic parts that are structured to be snapped together and snapped apart when necessary to replace damaged portions thereof while also providing a container which, when collapsed, requires a storage floor space less than that required for the unfolded case, that is stackable in a secure manner onto another such collapsed case, and that takes up a volume between about 1/3 and 1/5 of the volume taken up by the opened, unfolded case, all while including hinge means and assembly means that are of durable construction and that provide operative interengagements that facilitate automated opening of the folded cases while providing positive locking of the case in its fully unfolded condition such that its walls will neither prematurely collapse nor buckle outwardly when filled or partially filled with individual containers, such as those used in marketing dairy products, fruit juices and the like.
It is accordingly a general object of this invention to provide an improved foldable packing case.
Another object of the present invention is to provide an improved foldable packing case for transporting and storing a plurality of items such as cartons containing dairy products or the like.
Another object of this invention is to provide an improved foldable packaging case that is constructed of a plurality of members that are operatively interconnected with each other by snap-together means that are molded onto each respective member as a unitary component part.
A further object of the present invention is an improved foldable packing case that, when folded, provides two generally parallel panel members that are structured such that a plurality of the improved foldable packaging cases have aligning mating portions that engage one folded case with another folded case for enhancing the stability of stacks of folded cases one upon another.
Another object of the present invention is to provide an improved foldable packaging device containing no metal inserts while providing hinge means having portions that rotate relative to each other when the packaging case is moved between its open condition and its closed condition.
Another object of this invention is an improved packaging case constructed of but one type of material or materials having similar coefficients of thermal expansion in order to avoid differences in expansion or contraction of individual parts upon storage in cooled environments or upon washing with hot solutions, which differences could lead to disfigurement of or structural damage to the case.
Another object of this invention is an improved foldable packaging case that significantly reduces storage space required when not in use and reduces the amount of space needed to haul the folded containers back to the refilling location to thereby reduce the round trip mileage of a delivery truck by permitting folded cases to be picked up by and stored within the limited free space within the truck trailer while the trailer is on its rounds delivering such cases that are unfolded and full of dairy products or the like.